1. Field of the Invention
The invention relates generally to telephone line check systems and, more particularly, but not by way of limitation, it relates to a system for performing line check of such as community dial offices that presently have only limited means for checking.
2. Description of the Prior Art
There are included in the prior art numerous types of telephone testing systems as they have been devised over the years for adaptation to the various telephone switching systems. More recently, specific centralized test systems such as the Model MLT-1 and MLT-2 developed by American Telephone & Telegraph Co. have found large application for mechanized loop testing of latter day telephone switching systems.
There still remain in this country a large number of small class 5 step-by-step offices that are commonly referred to as "community dial offices" (CDO). Such exchanges are usually unattended and maintained by roving technicians as necessitated by trouble occurrences, and while these exchanges are scheduled for replacement by digital equipment within the next decade, there will be little or no automated testing in the meantime. For the most part the Model MLT remote systems are prohibitive on economic $30,000.
The need for a low cost device that will provide craft technician access to cable pairs terminating on main distribution frames in these types of small telephone offices is extant today. A presently available device is the DATU unit available from Harris-Dracon Division. The DATU equipment is capable of performing varied ones of the requisite test functions that are needed in a community dial office environment. Another form of test equipment that is presently available is the Series 3703 Local Cabinet that is manufactured and distributed by Northern Telecom. Finally, a test system interface for telephone loop maintenance and performing isolated ones of the requisite tests is produced by Ericsson GmbA of Sweden. While these various commercially available test units can function to provide isolated ones of the access and testing procedures, there is a need for an equipment of much reduced expense and having multiple capabilities that will allow a craftsperson to quickly verify that telephone line connections are correct and in good order in and about a rural community dial office environment.